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Revision 580e4273d7a883ececfefa692c1f96bdbacb99b5 authored by Cong Wang on 02 October 2020, 19:13:34 UTC, committed by David S. Miller on 04 October 2020, 21:53:06 UTC 
net_sched: check error pointer in tcf_dump_walker()
 
Although we take RTNL on dump path, it is possible to
skip RTNL on insertion path. So the following race condition
is possible:

rtnl_lock()		// no rtnl lock
			mutex_lock(&idrinfo->lock);
			// insert ERR_PTR(-EBUSY)
			mutex_unlock(&idrinfo->lock);
tc_dump_action()
rtnl_unlock()

So we have to skip those temporary -EBUSY entries on dump path
too.

Reported-and-tested-by: syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")
Cc: Vlad Buslov <vladbu@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 9a9e774
Raw File
debug_page_ref.c 
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm_types.h>
#include <linux/tracepoint.h>

#define CREATE_TRACE_POINTS
#include <trace/events/page_ref.h>

void __page_ref_set(struct page *page, int v)
{
	trace_page_ref_set(page, v);
}
EXPORT_SYMBOL(__page_ref_set);
EXPORT_TRACEPOINT_SYMBOL(page_ref_set);

void __page_ref_mod(struct page *page, int v)
{
	trace_page_ref_mod(page, v);
}
EXPORT_SYMBOL(__page_ref_mod);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod);

void __page_ref_mod_and_test(struct page *page, int v, int ret)
{
	trace_page_ref_mod_and_test(page, v, ret);
}
EXPORT_SYMBOL(__page_ref_mod_and_test);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_test);

void __page_ref_mod_and_return(struct page *page, int v, int ret)
{
	trace_page_ref_mod_and_return(page, v, ret);
}
EXPORT_SYMBOL(__page_ref_mod_and_return);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_return);

void __page_ref_mod_unless(struct page *page, int v, int u)
{
	trace_page_ref_mod_unless(page, v, u);
}
EXPORT_SYMBOL(__page_ref_mod_unless);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_unless);

void __page_ref_freeze(struct page *page, int v, int ret)
{
	trace_page_ref_freeze(page, v, ret);
}
EXPORT_SYMBOL(__page_ref_freeze);
EXPORT_TRACEPOINT_SYMBOL(page_ref_freeze);

void __page_ref_unfreeze(struct page *page, int v)
{
	trace_page_ref_unfreeze(page, v);
}
EXPORT_SYMBOL(__page_ref_unfreeze);
EXPORT_TRACEPOINT_SYMBOL(page_ref_unfreeze);
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